Add Support for "track_total_hits" to Accurately Track Total Hits Above 10K

Issue:
Django Haystack currently does not support the track_total_hits parameter, leading to inaccurate hit counts when the total exceeds 10,000 (due to Elasticsearch's default limit).

Suggestion:
We can add an option in the Elasticsearch backend to enable track_total_hits, allowing users to get accurate total hit counts above 10,000.

if settings.TRACK_TOTAL_HITS: 
    search_kwargs["track_total_hits"] = "true"

This could be added within the search method of elasticsearch_backend.py, allowing users to enable accurate hit tracking.

Reference:
Elasticsearch: Track Total Hits

Start in haystack/backends/elasticsearch_backend.py at the search method linked in the issue, then read the Elasticsearch Track Total Hits reference. Determine how the backend option should be exposed and verified; done means users can enable accurate total hit counts beyond 10,000.